BirdAnalyst
Species · Washington · BBS 2025 Release · 1966–2024

Harlequin Duck Population Trend in Washington

All statesWaterfowl

Harlequin Duck in Washington has fallen sharply: down 73% on the route-weighted index since 2000.

-73%Since 2000TrendPercent change in the route-weighted abundance index between a smoothed baseline window and the most recent one. It tracks direction, not absolute population.Full methodology →
5Routes In StateSurvey routesHow many standard-protocol BBS routes contributed counts. More routes means a steadier, better-sampled index; very thin coverage is suppressed.Full methodology →
13YearsYears surveyedNumber of years with at least one standard-protocol run in this geography. A longer record makes the trend more reliable.Full methodology →

Notable Harlequin Duck Trends in WashingtonNotable signalsLong-arc shifts the engine flags automatically — sustained declines or increases large enough to stand out from year-to-year noise.Full methodology →

long arc declinecomputed indexTrend sourceWhether the figure is our own computed route-weighted index or an official USGS modeled estimate. The current build labels every trend as computed.Full methodology →

Harlequin Duck has fallen sharply in Washington: down 73% on the route-weighted index since 2000.

Harlequin Duck Survey Routes in Washington

Routes recording Harlequin Duck in Washington.
Recent countThe raw number of individuals recorded on this route in its most recent survey year. A single-route tally, not a trend.Full methodology →
Twisp320001983
Warm Beach220062006
Hurricane Rg220232000
Mazama120182018
Winthrop120012001

Harlequin Duck Population Trend in Other States

alaskacaliforniaidahomontanaoregonwyoming

Source: USGS North American Breeding Bird Survey, retrieved 2026-05-22.